Process for manufacturing asphalt plastisols



United States Patent PROCESS FOR MANUFACTURING ASPHALT PLASTISOLS JohnC. Illman, El Cerrito, Calif., assignor to Shell Development Company,New York, N. Y., a corporation of Delaware No Drawing. Application June27, 1955 Serial No. 518,393

6 Claims. (Cl. 208-45) This invention relates to a process for thepreparation of asphalt plastisols. More particularly, it is concernedwith the preparation of asphalt plastisols having improved stability.

The term plastisol is well known in the plastics and coating arts andhas reference to a fluid or pasty mixture or suspension of a coatingmaterial in particulate form with a plasticizer which is a poor solventfor the resin or polymer at ordinary temperatures, but which is capableof dissolving the particles at elevated temperatures, forming a gelstructure. Plastisols have afforded a convenient and economical means offabricating molded or coated articles from certain restricted classes ofthermoplastic resins such as by spread molding, dip coating, spraying orslush molding. For instance, to make a shaped article, a mold of adesired shape is simply charged with plastisol, heated to cause theplastisol to coalesce and then cooled, whereupon the plastisol becomesrigid; the article retains the desired shape after removal-from themold.

For certain purposes, e. g., for charging molds or coating cloth, it isdesirable to employ smooth fluid plastisols which flow rapidly in orderto increase the speed and convenience of the fabricating operation aswell as to improve the quality of the fabricated article. ly viscousplastisols which may in fact be pastelike in consistency are oftenformed but are generally undesirable.

Heretofore the type of resinous material found most suitable for use inplastisol processes included especially the polyvinyls, such aspolyvinyl chloride. The limitation upon the process has been thetendency of most film-forming materials when in particulate form ofsuitable subdivision to dissolve gradually in the suspendingplasticizers upon storage. Y

The application of bituminous compositions has always been complicatedby the viscosity of the bitumen. Under certain ordinary conditions oftemperature it has been possible to overcome this disadvantage by theemployment of aqueous asphalt emulsions and the like, controlling theviscosity of the emulsion by a number of well-known means. However, suchemulsions cannot be used at freezing temperatures and require thetransport of large amounts of water. Cutbacks utilizing relativelyvolatile thinners are commonly employed. Fire hazards are involved intheir use, as well as inefficient utilization of the thinner, which islost by eventual volatilization. On the other hand, asphalts sometimesmay be applied at elevated temperatures for the purpose of decreasingtheir viscosity. Thishas the disadvantage of requiring hot storage orhot transporation or the presence More high- Patented Dec. 2, 1958 ofheating and melting equipment at the point of application, all of suchrequirements being uneconomical if they can be avoided. Significantlimitations on the application of heated asphalts for such purposes asimpregnation of roofing felts, are the fire hazard which is alwayspresent at such times, and skin formation during hot storage. Attropical temperatures handling difficulties arise due to theimpossibility of fracturing the highly viscous mass of asphalt fromshipping drums for the purpose of charging it into melting pots.

Many of these problems have been solved by the compositions described incopending patent application Serial No. 391,126, filed November 9, 1953,by Illman et al. Therein, asphalt plastisols are described, the hardasphalt particles being suspended in a suitable type of lighterpetroleum fractions which, upon heating, coalesce with the asphaltparticles to form an asphalt suitable for such purposes as paving orroofing. The problem of preventing the solution of the asphalt particlesin the suspending liquid medium was solved to a certain extent byproviding the particles with a solvent resistant surface, such as byrinsing with heptane, or by providing the particles with resinous orplastic coatings. While these steps provided asphalt plastisols ofsatisfactory stability for some purposes, it is recognized that thesestabilizing steps disclosed in the copending application necessitateincreased operation costs which it would be well to avoid.

It is an object of the present invention to provide improved methods forthe preparation of stable asphalt plastisols. It is a specific object ofthis invention to provide such plastisols which are stable 'overrelatively long storage periods. It is another object of this inventionto enable the use of asphalts from a greater diversity of sources thanheretofore possible. It is a further object of the invention to enablethe preparation of plastisols having lower viscosities for a givenasphalt content than heretofore possible. It is an additional object ofthe invention to provide a less expensive means of preparing asphaltplastisols. Other objects will become apparent from the followingdescription of the invention.

Now, in accordance with the present invention, it has been found thatstable asphalt plastisols may be prepared by first mixing a fluidasphaltic residue with a relatively large volume of a lower aliphatichydrocarbon whereby asphaltenes are precipitated in suitable particlesize and the maltenes present in the asphaltic residue dissolve in thealiphatic hydrocarbon. Subsequently, according to the present process,the asphaltenes are separated from the dissolved maltenes and thereafterincorporated with a suitable petroleum fraction suspending fluid toprovide asphalt plastisols having improved resistance to undesirablesolution during storage.

More particularly, the process of the present invention comprisesforming a liquid asphaltic residue, combining l volume of said residuewith between about 3 and about 50 volumes (preferably 5-30) of analiphatic hydrocarbon medium predominating (more than about by weight)in substantially straight chain hydrocarbons having from 5 to 12(preferably 6-9) carbon atoms per molecule, whereby asphaltenes areprecipitated and maltenes are dissolved in the medium. The precipitatedasphaltenes, after separation from the maltene solution,

are then combined with a petroleum fraction having a' viscosity betweenabout SUS at 100 F. and about 3 300 SUS at 210 F. It has been found, inaccordance with the present invention, that plastisols so formed havemaximum resistance to solution in the suspending petroleum fractionduring storage and are prepared by the cheapest known means.

One of the chief advantages gained by the use of the present inventioncomprises the far greater possibility of selection of suitable stocksfor use in the preparation of asphalt plastisols. As contemplatedheretofore, asphalt plastisol preparation required the use of an asphalthaving a sufficiently brittle character so that fine particles could beprepared by grinding or other known means. Consequently, the more widelyavailable softer grades of asphalts could not be used. By the use of thepresent invention, however, it is possible to employ asphalts of anydegree of hardness and from any source. Economically, of course, it ispreferable to employ an asphalt having at least about 5% by weight ofasphaltenes and preferably more than about 20% by weight of asphaltenesso as to have a minimum of disposable maltene fractions dissolved in thealiphatic hydrocarbon medium. Hence, it will be understood that not onlyhard asphalts, i." e. having penetrations from to 10 (ASTM D-25, 77 F.,100 gram load, 5 seconds), but also otherrelatively softer asphalticresidues, preferably having a maximum of 200 penetration, and suchmaterial as residual industrial fuel oils having viscosities as low asabout 45 S. S. F., at 122 F., for example, 45-300 S. S. F., asmeasuredby the same test; In addition to such penetrationcharacteristics, the asphalts will generally have softening pointsbetween about 90 F. and about 350 F. They include straight run asphalts,steam distilled asphalts, blown asphalts, solvent refined asphalts,cracked asphalts, vacuum flashed asphalts and similar asphalticresidues, all of which preferably comprise at least about 5% by weightof asphaltenes. The term asphaltenes" is defined in Abraham, fifthedition, of Asphalts and Allied Substances on pages l1656, as being thenon-mineral con stituents remaining insoluble in petroleum naphtha, thusdifferentiating them from the 'malten'es (petrolenes) which dissolve inthe same medium and under the same conditions. "As the test is run atroom temperature (6575 F.), this latter would constitute a furtherlimitation on the definition. A still further limitation will cornprisethe proportion of petroleum naphtha employed for the purpose of causingthe separation. According to the standardized method, '50 volumes ofpetroleum naphtha are employed, the test temperature normally beingambient (room) temperature; While this standard procedure defines theterm, it will be understood that the asphaltic fraction insoluble atroom temperature in any aliphatic hydrocarbon having 5-12 carbon atomsmay be regarded as asphaltene for the present invention.

The copending application Serial No.391,126 describes suitable methodsof the preparation of relatively hard types of asphalts by steamdistillation, propane precipita tion or oxidation such as by airblowing. While all of these methods are useful for the preparation ofasphalts to be employed in the present process, any other means for thepreparation of asphaltic residues may be employed, as long asthe productproduced contains an economically feasible (more than 5% byweight)proportion of asphaltenes and preferably has a penetration less thanabout 200 at 77 F. i v i The asphalts may be introduced into thealiphatic hydrocarbon'precipitant by several alternative means, de-

pendent upon their physical characteristics; For'example,

har'dasphalts (especially cracked'or blown), i; eithose having apenetration at 77 P. less than about 10, are preferably introduced byfirst dissolving them in a minimum amount of an aromatichydrocarbon'solve'nt. In

order to minimize the effect of the'solvent upon the precipitation ofthe asphaltenes, it is preferred that the and 2 volumes for each volumeof .the asphaltic residue.

The aromatic solvent is preferably one predominating in aromatichydrocarbons having less than 10 carbon atoms per molecule of whichbenezene and toluene are suitable members. Preferably, the aromaticsolvent contains at least about 70% by weight of such aromatichydrocarbons and more desirably contains or more of such hydrocarbons.The solution may take place at room temperature or, preferably, atreflux temperature in order to hasten the process. Softer asphalts, i.e. those having penetrations greater than about 10 at 77 F., may bedispersed sufficiently for the present purpose by refluxing in thepresence of a limited proportion of the precipitating aliphatichydrocarbon, "although the aromatic solvent may be used in addition toor in place of the aliphatic medium. The proportion again is preferablylimited to between about 0.5 and 2 volumes of the refluxing medium foreach volume of the asphalt, regardless of whether or not the refluxingmedium comprises entirely aliphatic hydrocarbons having between 5 and 12carbon atoms per molecule or additionally contains aromatic hydrocarbonsas well.

Of course, the asphalt may be introduced into the aliphatic hydrocarbonmedium for the purpose of precipitation asphaltenes in the form of aheated fluid asphaltic residue unmodified by the presence of limitedproportions of aromatic or aliphatic hydrocarbons.

The. precipitation step is believed to be important, since it carriedout counter to the following disclosed procedure, the particles ofasphaltenes so derived-are undesirably small and tend to dissolve at amuch more rapid rate than if prepared according to the described andclaimed process.

In order to obtain the desirable range of asphaltene particle size, itis necessary to add the fluid asphaltic residue to a substantiallylarger body of aliphatic hydrocarbon medium.

By aliphatic hydrocarbon medium, in this particular instance, is meantone or more aliphatic hydrocarbons having from 5 to 12 carbon atoms permolecule and preferably predominantly straight chain varieties of thesematerials. The medium shouldcontain no more than about 25%- by volume ofnon-aliphatic materials and preferably less than about 10% by volume.Individual aliphatic hydrocarbons such as hexane, heptane, octane,nonane, decane and dodecane may be employed, the straight chain (normal)isomers of these being preferred. However, mixtures of these .materialsmay be employed which are prepared either synthetically or may occur asdistilation fractions or components ofnaturally occurring mixtures suchas certain crudes. Thus, de-pentanized natural gasoline or similarfractions may be employed having'a'minimum of about 6 carbon atoms permole cule and a maximum boiling point below about 300 F.

By a substantially larger volume is meant addition of 1 volume of theasphaltic residue to 3-50 volumes and preferably between 5 and/30.volumes ofthe aliphatic hydrocarbon medium.

It is necessary for the residue to be added to at least 3 volumes of the,aliphatichydrocarbon medium in order toobtain the proper particle sizedistribution, since if.

the reverse process is employed, i. e. gradual dilution of thefluidizedasphaltic residue with aliphatic hydrocarbons, then theasphaltenes so precipitated have been found to be of such small particlesize that they form a more viscous dispersion and dissolve in thesuspending oil later employed at much too rapid a rate to besatisfactory.f If, however, the correct' procedure is utilized,

the resultingprecipitated a'sphaltene pa'rticels have dianieters withinthe range of about 1 micron to about ZOO microns and predominate in aparticle size range of be tween about 10 and about 50 microns in averagediametei'. 'It will be understood that the coarser the particle size,consistent with tendency of larger particles to settle on storage, theslower the rate of solution of the particles in the suspendingplastisol, oil.

The fluid or liquefied (dissolved) asphalticresiduemay be added to thealiphatic hydrocarbon medium at any temperature between the freezingpoint of the medium and the boiling point thereof. Preferably, ofcourse, the

liquid asphaltic residue is mixed with the aliphatic hydrocarbon mediumat about room temperature or within a temperature range from about F. toabout 110 F. Under these circumstances the rate of solution of themaltene fraction in the aliphatic hydrocarbon medium is reasonably rapidand the asphaltenes consequently precipitate in their proper particlesize distribution range. The introduction of the liquid asphalticresidue into the aliphatic hydrocarbon medium is preferably conducted inthe presence of agitation. mechanical shaking, stirring or tumbling ofthe mixture, the agitation may be provided by refluxing of the medium ifthis condition is part of the precipitation process. It was noted thatasphaltene particles prepared from straight run asphalts grew oragglomerated to a desirable extent when left in the precipitating mediumfor a period of 148 hours at ambient temperature.

Following the precipitation of the asphaltenes and solution of themaltenes in the aliphatic hydrocarbon medium, the solution and theprecipitated particles are separated by any suitable means, includingfiltration, centrifuging, sedimentation, decanting or similartreatments. 'Preferably the separation is such that a minimum amount ofdrying of the asphaltene particles is required (if any at all) and stillmore preferably, the separation technique employed is one wherein aminimum contamination of the particles with maltene solution occurs.

The separated asphaltene particles, in accordance with the subsequentstep in the process of the invention, are incorporated in the plastisolsuspending medium.

In selecting a fluid medium for suspension of the particulate hardasphalt in accordance with this invention, it is the intention toutilize a material which, when coalesced with the asphalt, will producea substantially homogene- 011s bituminous composition exhibiting theproperties desired in a normal asphalt paving or roofing composition.Thus, the suspending oil should be of such composition that it not onlydoes not exhibit an undue rate of solution of the asphalt particles, butwhen subsequently coalesced with the latter, it will be substantiallycompatible therewith without any substantial removal or addition theretoin the form of supplementary fiuxing ingredients. For example, theplastisols contemplated herein do not make use of relatively volatileflux oils (such as kerosene or fuel oil) wherein a substantialproportion of the oil is eventually volatilized from the composition.Nor is use to be made exclusively of oily aliphatic hydrocarbon oils,since such oils, in spite of being satisfactory with respect toplastisol stability, exhibit poor compatibility with the asphalt afterattempting coalescence. Furthermore, the exclusive use of highlyaromatic oils such as lubricating oil extracts is not contemplated,since the latter, while forming compatible compositions, tend to causerapid dissolution of the asphalt particles during storage even in theabsence of heating.

Taking each of these facts into consideration, therefore, the presentinvention contemplates the use of a hydrocarbon oil of lubricating oilviscosity containing between about and about 60%' of aromatic typehydrocarbons as the principal suspending oil. For application underextremely cold, e. g. arctic, conditions, the addition of minorquantities of lighter oils, preferably of aliphatic character may beutilized, but the major proportion of spending oil should be thatdefined above. .Thus,.

organosol type of compositions are contemplated wherein compatible ornon-compatible relatively volatile diluents are used in addition to theoil of lubricating viscosity.

Suitable lubricating oil or pale oil fractions which may be employedinclude bulk distillates having a viscosity of from about 100 SUS at100? F. to about 300 SUS at 210 F. and may contain aromatics in theorder of While this may comprise 30-60% and flash points about 300 F.,particularly where paving grade asphalt compositions are contemplated.Preferably these fractions are essentially nonwaxy. Where blown typeasphalt compositions are desired, the aromatic hydrocarbon contentshould be still lower, in the order of 1530% aromatics. Reference toaromatics is given in terms of infra red analyses. Suitable lubricatingoil fractions comprise bulk lubricating oil distillates or fractionsthereof, and lubricating oil raflinates obtained from the extraction oflubricating oil fractions with selective solvents for aromatics such assulfur dioxide, phenol, sulfolane, nitrobenzene, furfural, and the like.These rafiinates are well known in the art of petroleum refining.Combinations of extracts and raffinates also are suitable. Thehydrocarbon lubricating oil may be replaced entirely or in part withsynthetic lubricants of similar viscosity, volatility and solvencycharacteristics, e. g. tetraalkyl silicates, silicones, aliphaticdiesters, etc.

In addition to the types of hydrocarbon oils specified as suspendingmedia for the asphaltene particles, other materials may be employedtogether with or in place of these substances. For example, it ispossible to employ all or a part of the maltenes separated from theasphaltenes in the previous asphaltene precipitation step. These may becombined with a lubricating oil falling within the limitations givenhereinbefore for the suspending oils, preferably in amounts of at leastabout 10% by weight of the suspending oil. Under these circumstances,the reconstituted asphalt which is prepared by coalescence of theparticles with the suspending oil, has all of the proper combination ofproperties desired in an asphalt. For many purposes, however, theincorporation of maltenes is unnecessary. Moreover, it is possible toemploy maltencs from an entirely different source than that fromwhichthe asphaltene particles are derived. Thus, it will be seen that aselection is possible, a desirable type of asphaltene being obtainedfrom one source while a desirable type of maltene is obtained from anentirely different source. By proper incorporation of selectedasphaltenes and maltenes it is possible to prepare may be employed. Thephenomenon is especially notable in that it makes the asphalteneparticles even more resistant to solution in the suspending oils thanwhen they are in their original precipitated condition. It is merelynecessary to precipitate the asphaltene particles as describedhereinbefore and then expose them in relatively shallow layers, i. e.less than one inch, to the action of ultra violet light, oxygen, S0chlorine or other oxidizing medium, for a period varying from about 15minutes to about 1 week (preferably 1-98 hours), at temperatures fromabout 50 F. to about F. Preferably the eX- posed material isperiodically stirred or agitated to expose all particles to'themodifying influence. Subsequent to this exposure period, the particlesare then suspended in the above-described suspending oils for thepreparation of plastisols having still further increased stabilityagainst solution of the particles in the suspending oil.

It is not apparent at the present time what takes place during thisexposure to ultra violet light or oxidizing influences. The change wouldappear to be superficial, that it, restricted to the surface ofthe-particles, since the asphalts reconstituted upon solution of theparticles in a suspending oil are substantially identical to asphaltsreconstituted from unexposed particles in the same oils.

additionof theprecipitated asphaltene particles to the. suspending oilwith suflicient agitation to. cause the for.

applications), orby application of a uniform amount.

by use of doctor: blade technique, .as: in application to roofingfelts,- fabricsc'and the like. When utili'zedfor paving purposes, theplastisol may. be sprayed=on.'.the-

hot orcold aggregate either in situ or in a :miXingfapparatus such as acement .mixert Alternatively, tne plastiol may=be heated inordertocoalesce'theingredients prior toapplicationto aggregateor other-solidbase'susbstance, Subsequent-t0 the application of 'the plastisol,sufficient heat should be applied O die-C0111" position to accelerate/coalescence of the asphalt particles with the suspending oil to formessentially a homo-geneous asphalt composition-havingthe'normalproperties of asphalts employed for paving, saturation or coa-tingpurposes. The heat may be supplied byutilizing preheated aggregate. Thedegree of heatingrequired will vary quite widely dependent upon thecompatibility-of the asphalt particles with the-oil and upon thequantity of asphalt plastisol to be coalesced. Normally arelaaccordingjto the data, that the-asphaltic pitch was'dissolved in:var'ious, quantitiesnof benzene was to provide a fluid or liquifiedproduct. This fluid product-was then introduced with rapid stirring intoheptane at room tem:

' perature, the ratioofheptaneto pitch being: variedas shown in thetable. By this means, as the data. show, varyingamounts of asphalteneswere 'precipitated'in suitableiparticle' size-for the preparation ofplastisols. These asphaltenes were washedlightly with heptane orpentane,

drained on a filter plate, and air dried. A bulkdi'stillate lubricatingoil from a mixture of'Mt Poso and Coalinga California crudes, havingaviscosity of .60 SUS at 210' F.

was employed as the suspending medium for the plastisols. It=will beseen, according to the data, that between and of asphaltenes, based onthe total plastisol, was mixed with the-bulk distillate to-prepare Thesehad originally low viscosithe subject plastisols. ties which at theendof one week at 100 1 had increased only to a limitedextent.

The bulk distillate and asphalt eneswere coalesced to Table I B enzenePitch Wt. Ratio Sample Heptanc Pitch Ratio Asphaltenes Plastlsol AsphaltViscosity at Percent 100 F., polses Asphaltene Percent w. Pen.

Size, n

Orig. 1 Week l-lOU tures such'as-pavements and the like are to betreated;

EXAMPLE II The same series of steps was carried out but-on an asphaltderived from a Los Angeles Basin California crude by mildly thermallycracking a reduced crude therefrom and removing the distillate materialunder vacuum. The asphalt had a softening point of 233 F;

and represented 19.4% of the long residue (reduced crude). Table IIshows the results obtained by the preparation of plastisols according tothe process of the present invention.

T able II Benzene: Pitgh Sample W Ratio Asphaltenes Plastlsol AsphaltViscosity at Percent 100 F;, poises Asphaltene Per- 7 Size, cent w. p.Pen.

Orig. 1 Week een;

cm- H S l -i lzinin open flame type of heatersmay be utilized althoughthey are not always essential.

EXAMPLE I The asphalt utilized'in the preparation of the samplesdescribed'in' Table I. was derived by vacuum flashing a longresidueobtained from the refining of'a California crude.

The vacuum flashed asphalt had a softening point of 222" Table- I-describes 'avariety' of conditions' employed in the preparation ofplastisols according to' the process of the present invention. It'willbeseen,

EXAMPLE III The. data" contained 'in'Table'IlI indicate'the resultsobtained by. the preparation of plastisols from avariety.

of asphalts as indicated in the left-hand column. It will" be seen thathighly stable plastisol compositions couldbe formed from any one ofthese and that by choosing. the original asphalt for a particularpurpose,

the properties of the final product could be closely con-.

trolled.

. Table III Asphaltenes Plastisol Asphalt Benzene: Hep- Asphalt Pitchtane: Viscosity at Wt. Pitch Per- Size, Percent 100 F., poises RatioRatio cent w. n Azphal- Pen. S. P. P. I

one

Orig. IWeek Cracked Venezuelan aspha1t. 1. 5:1 40:] 52 12 16 54 183 +5.1 Straight Run Venezuelan,

180/200 Pen"-.. 1:1 40:1 14 1-400 35 13 275 102 Calif. Coastal,

200 Pen 1:1 40:1 21 1200 35 17 1, 500 225 107 +1.3 Los Augelcs Basin,Butane,

Asphalt 0.75:1 40:1 38 1-150 35 12 170 240 98 -0.7 Calif. CoastalAsphalt 40:1 23 1-100 35 12 147 225 103 +0. 4

EXAMPLE IV ployed was the secondary-column tops described in In each ofExamples I-III, heptane was employed as the precipitating medium for theasphaltenes. Table IV shows that other media are suitable for theprecipitation of asphaltenes which are useful in the preparation 25 ofplastisols according to the process of the present invention. Theprecipitant employed in this example comprised secondary-column tops,consisting of gasolines including hexanes and other hydrocarbons havinga maximum boiling point of about 300 F. A variety of asphalts wastreated, the vacuum flashed asphalt being the same as that utilized inExample I; the cracked asphalt being that utilized in Example II, whilethe California Coastal 200 pen, asphalt was the same as that employed inthe procedure described in Example III. It will be noted that the use ofthe secondary-column tops produced a smaller proportion of asphaltenesthan when heptane was employed and that the asphalts derived by ExampleIV. Asphaltenes so precipitated were substantially immediatelyincorporated with 60 SUS at 210 F. bulk distillate utilized in theprevious Examples to form a plastisol having an original low viscositywhich increased to 1500 poises at the end of one week. Part of theprecipitated asphaltenes were exposed for about 3 days at roomtemperature to weak sunlight in a layer about one-quarter of an inchthick. Upon inc0rporation with the same bulk distillate and storage at100 F.

0 it will be seen, according to Table V, that the increase in viscositywas only about 5% as great as in the case of the unexposed asphalteneplastisol. is evident that such treatment promotes the preparation ofplastisols having maximum stability with respect to viscosity increase.The properties of the asphalts derived from these two plastisols werequite similar and do not indicate that any drastic change in the mainbody of the asphaltenes occurred during this exposure period.

Table V Asphaltenes Plastisol Asphalt Benzene: Tops: Sample Pitch WtPitch Viscosity at Ratio Ratio Per- Percent 1009 F., poises cent w. Size,u Asphal- Pen. S. P. P. I.

tene

Orig. 1 Week No asphaltene aging 40:1 11. 5 1-150 35 12 1, 500 115 127+1. 9 Asphaltene Aged. 40:1 11. 6 l-l 35 14 83 147 +2. 3

coalescence of the plastisols all had higher penetration indices (P. I.)than when heptane was the precipitant.

I claim as my invention:

1. In the process for the preparation of an asphalt Table IV AsphaltenesPlastisol Asphalt Benzene: Tops: Sample Pitch Wt Pitch Viscosity atRatio Ratio Per- Percent 100 F., poises centw. Size .1 Asphal- Pen. S.P. P. I

tene

Orig. lWeek Vacuum Flashed. 1. 5:1 40:1 22. 5 5-50 35 10 1, 700 95 131+1.0 Cracked 1:1 40:1 45 6-80 35 12 30 62 157 +3. 4 Calif. Coastal 200Pen 1.521 40:1 9 5-50 3 11 93 137 +2.6

EXAMPLE V plastisol, the steps comprising forming a fluid body of Thecomparative data in Table V illustrate the adan asphalt Said asphaltComprising more than by vantages gained by exposing the precipitatedasphaltenes to the action of ultra violet light, namely difused sunlightat room temperature. The original asphalt employed for the preparationof the asphaltenes was derived by topping California Coastal crude. Theprecipitant em- Weight of asphaltenes by dissolving one volume of theresidue in 0.5-2 volumes of an aromatic solvent, said solventpredominating in aromatic hydrocarbons having less than 10 carbon atomsper molecule, introducing one volume 5 of the asphalt into 3-50 volumesof an aliphatic hydro- Consequently, it

11 carbon medium, said medium comprising predominantly straight chainparafiin hydrocarbons having from six to twelve carbon atoms permolecule and less than 25% by weight of aromatic hydrocarbons, wherebyasphaltene particles having a size distribution between about i'micronand about 200 microns precipitate and maltenes dis" solve in thealiphatic hydrocarbon-medium separatin the precipitated asphaltenes fromdissolved maltenes, and; suspending the asphaltenes in apetroleunrfractionhaving a viscosity between about 100 SUS at 100 F. and

about 300 SUS at 210 F. and an aromatic content between about and about60%, whereby a stable plastisol composition containing-less -than about40%- by weight of asphaltenes is formed:

2. In the process for the preparation of an asphalt 15 plastisol, thesteps comprising forming a fluid body of a cracked asphalt, said asphaltcomprising more than 209;, by weight of asphaltenes by dissolving onevolume of the residue in 0.5-2 volumes of an aromatic solvent, saidsolvent predominating-:in.aromatic hydrocarbons having;

less-thanwlO carbon atoms per molecule, introducing one volume of theasphalt'into.5,30 volumes'ohan aliphatic hydrocarbon medium, said mediumcomprising predom: inantly straight chain paralfin hydrocarbons havingfrom six to twelve carbon atomsperrnolecule and less than 25% by weightof aromatic hydrocarbons,. whereby. asphaltene particles having. a.sizedistribution between about 1 micron and about 200 microns precipitateand maltenes dissolve in the aliphatic hydrocarbon medium,

separating .theprecipitated asphaltenes from dissolved maltenes, andsuspending the asphaltencs in a petroleum fraction having a viscositybetween about 100 SUS at 100 F. and about 300 SUS at 210 F., and anaromatic hydrocarbon content between about 15% and about 60%, whereby astable plastisol composition containing less than about 40% by weight ofasphaltenes is formed.

3. In the process for the preparation of an asphalt plastisol, the stepscomprising forming a fiuid' body of an asphaltic residue comprising morethan, 5% by weight of asphaltenes and having a penetration less thanabout 12 10 at 77 F. ,by dissolving one volume of the residue in 0.5-2volumes of an aromatic solvent, said solvent predominating in aromatichydrocarbons having less thanlO carbon atoms per molecule, introducingone volume of the asphalt into 5-30volumes of an aliphatic hydrocarbonmedium, said medium comprising predominantly straight chain paraffinhydrocarbons having from six to twelve carbon atoms per molecule andless than 25% by weight of aromatic hydrocarbons, whereby asphalteneparticles having a size distribution between' about 1 micron and about200 microns precipitate and maltenes dissolve in the aliphatichydrocarbon, medium, separating the precipitated asphalte'nes fromdissolved maltenes, and suspending theasphaltenes in a petroleumfraction having a viscosity between about 100 SUS at- 100 F. and about300 SUS at 210 F. and an aromatic centent between about 15% and aboutwhereby a stable plastisol composition containing less than about 40% byweight of asphaltenes is formed.

4. A process accordingto. claim 1 wherein the as- References Cited inthe file of this patent UNITED STATES PATENTS 1,868,211 Le Nobel July19, 1932 2,200,484 Batchelder May 14, 1940 2,201,396 Fryar May 21, 19402,366,657 Sorern Jan. 2, 1945 OTHER REFERENCES Abraham: Asphalts andAllied Substances, fifth edition, vol. 2, pages 1229, 1463 and 1464.Pub. by D. Van Nostrand Co., New York, N. Y. (1945).

1. IN THE PROCESS FOR THE PREPARATION OF AN ASPHALT PLASTISOL, THE STEPSCOMPRISING FORMING A FLUID BODY OF AN ASPHALT, SAID ASPHALT COMPRISINGMORE THAN 5% BY WEIGHT OF ASPHALTENES BY DISSOLVING ONE VOLUME OF THERESIDUE IN 0.5-2 VOUMES OF AN AROMATIC SOLVENT, SAID SOLVENTPREDOMINATING IN AROMATIC HYDROCARBONS HAVING LESS THAN 10 CARBON ATOMSPER MOLECULE, INTRODUCING ONE VOLUME OF THE ASPHALT INTO 3-50 VOLUMES OFAN ALIPHATIC HYDROCARBON MEDIUM, SAID MEDIUM COMPRISING PREDOMINANTLYSTRAIGHT CHAIN PARAFFIN HYDROCARNONS HAVING FROM SIX TO TWELVE CARBONATOMS PER MOLECULE AND LESS THAN 25% BY WEIGHT OF AROMATIC HYDROCARBONSWHEREBY ASPHALTENE PARTICLES HAVING A SIZE DISTIBUTION BETWEEN ABOUT 1MICRON AND ABOUT 200 MICRONS PRECIPITATE AND MALTENES DISSOLVE IN THEALIPHATIC HYDOCARBON MEDIUM SEPARATING THE PRECIPITATED ASPHALTENES FROMDISSOLVED MALTENES, AND SUSPENDING THE ASPHALTENES IN A PETROLEUMFRACTION HAVING AVISCOSITY BETWEEN ABOUT 100 SUS AT 100*F. AND ABOUT 300SUS AT 210*F. AND A AROMATIC CONTENT BETWEEN ABOUT 15% AND ABOUT 60%,WHEREBY A STABLE PLASTISOL COMPOSITION CONTAINING LESS THAN ABOUT 40% BYWEIGHT OF ASPHALTENES IS FORMED.